On 6/29/2016 4:56 PM, Colin Percival wrote: > Author: cperciva > Date: Wed Jun 29 23:56:24 2016 > New Revision: 302288 > URL: https://svnweb.freebsd.org/changeset/base/302288 > > Log: > Enable indirect segment I/Os by default in the Xen blkfront driver when > running on EC2. Due to improvements in EC2, the performance penalty which > was present on some EC2 instances no longer exists, and enabling this > feature now consistently yields ~20% higher throughput with equal or lower > latency.
Does this rely on any driver updates / is it safe to make the same
change on my existing 10.2 system?
>
> Reverts: r286063
> Approved by: re (gjb)
> MFC after: 2 weeks
> Relnotes: Improved disk throughput on EC2
>
> Modified:
> head/release/tools/ec2.conf
>
> Modified: head/release/tools/ec2.conf
> ==============================================================================
> --- head/release/tools/ec2.conf Wed Jun 29 23:33:44 2016
> (r302287)
> +++ head/release/tools/ec2.conf Wed Jun 29 23:56:24 2016
> (r302288)
> @@ -72,11 +72,6 @@ vm_extra_pre_umount() {
> # nodes, but apply the workaround just in case.
> echo 'hw.broken_txfifo="1"' >> ${DESTDIR}/boot/loader.conf
>
> - # Some EC2 instances suffer a significant (~40%) reduction in
> - # throughput when using blkif indirect segment I/Os. Disable this
> - # by default for now.
> - echo 'hw.xbd.xbd_enable_indirect="0"' >> ${DESTDIR}/boot/loader.conf
> -
> # Some EC2 instances run on a version of Xen which has a bug relating
> # to the migration of MSI-X interrupts; this is visible as SR-IOV
> # networking (aka. "EC2 Enhanced Networking") not being able to pass
>
--
Regards,
Bryan Drewery
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